A’la Hadrat رَحْمَةُ اللهِ تَعَالٰی عَلَيْه has stated: The Beloved and Blessed Rasool صَلَّى اللهُ تَعَالٰى عَلَيْهِ وَاٰلِهٖ وَسَلَّم performed Wudu and drank the leftover water of it in a standing position. And it is stated in a Hadees that this water is a cure for 70 diseases.
(Fatawa Razawiyyah, vol. 4, pp. 575)
Islamic jurists رَحِمَهُمُ الـلّٰـهُ تَـعَالٰی have said, ‘If one performs Wudu using some pot and some water is left over, it is Mustahab to drink that water while standing and facing the Qiblah.’
(Tabyeen-ul-Haqaaiq, vol. 1, pp. 44)
Regarding drinking the leftover water of Wudu, a Muslim doctor has stated:
1. It improves the functioning of the bladder, removing difficulty in passing urine.
One is freed from unlawful lust.
It removes burning of the liver, the stomach and the bladder.
صَلُّوۡا عَلَى الۡحَبِيۡب صَلَّى اللّٰهُ تَعَالٰى عَلٰى مُحَمَّد
Dear Islamic brothers! The topic of Wudu and science is being discussed. Nowadays people are more interested in science.